At the present time, many containers particularly for food products employ an inner seal, known as a "foil", sealed to the mouth of the container. The container additionally has a separate removable cap positioned over the foil and attached to the container by either a snap connection or a screw-type thread. Many of the machines for applying the foil and cap to the container rely on a technique whereby the foil is initially positioned within the cap, and the foil-cap combination is then attached to the container in a single assembly operation, which operation is such as to also effect sealing of the foil to the container mouth. With this type operation, however, it is difficult to determine if the foil properly seals against the container mouth. In fact, in some instances the foil may even fall out of the cap prior to the combination being attached to the container, and in such instance the sealing foil is missing and yet such can not be readily detected once the cap is attached to the container.
Accordingly, the present invention relates to an improved apparatus designed, in a preferred utilization thereof, for positioning and sealingly attaching a foil to the mouth of a container prior to and wholly independent of the attachment of the cap to the container.
In the apparatus of the present invention, there is preferably provided a rotatable turret having multiple sealing stations provided in circumferentially-spaced relationship therearound. Each sealing station has a removable stacker unit associated therewith, which unit holds therein a large quantity of vertically-stacked foils so as to permit the apparatus to operate for long periods of time without shut-down. A foil transfer unit is associated below each stacker unit but above each container-receiving location on the turret so that the lowermost foil can be removed from the stack, with the foil then being inverted by the transfer unit and lowered into sealing engagement with the mouth of the container. The container and the foil pass through an arcuately elongated heating structure, such as an induction heater, which extends circumferentially of the turret to ensure proper sealing attachment of the foil to the container mouth. The rotation of the apparatus, and the presence of multiple sealing stations positioned therearound, each having its own stacker unit and foil transfer unit, hence enables containers to be sealed at a rapid rate. Since the sealing occurs prior to application of the cap, inspection can be readily carried out to ensure that the foil is sealingly engaged with the container mouth.
Other objects and purposes of the invention will be apparent to persons familiar with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings.